Field
Signaling can be valuable in connection with addressing issues of interference. Signaling designs may be valuable, for example, in network-assisted interference cancellation and suppression.
Description of the Related Art
Network assisted interference cancellation and suppression (NAICS) is a study item for release 12 (Rel-12) of the third generation partnership project (3GPP).
NAICS may be related to a variety of receiver types. For example, NAICS may be related to interference rejection type receivers which include LMMSE-IRC (Linear MMSE-IRC), E-LMMSE-IRC (Enhanced Linear MMSE-IRC), and W-LMMSE-IRC (Widely Linear MMSE-IRC). For another example, NAICS may also be related to maximum likelihood type receivers which include ML (Maximum likelihood receiver), R-ML (Reduced complexity maximum likelihood receiver), and Iterative (R)-ML (Iterative maximum likelihood receiver or Iterative reduced complexity maximum likelihood receiver). For further example, NAICS may also be related to interference cancellation type receivers which include L-CWIC (Linear Codeword interference cancellation receiver), ML-CWIC (Maximum likelihood Codeword interference cancellation receiver), and SLIC (Symbol level interference cancellation type receiver).
Techniques developed under NAICS target interference suppression and interference cancellation (ISIC) at a user equipment (UE). They can be treated as an integral part of the whole portfolio of interference mitigation and interference cancellation/suppression (IMIC) in a communication system.
Conventional ways of facilitating UE performance of interference cancellation assume perfect physical downlink shared channel (PDSCH) allocation alignment between interference and desired PDSCH signal. These approaches have a common characteristic: the UE does not know the resource allocation information for the interference PDSCH. The interference PDSCH to the allocated bandwidth might be for different users, therefore the transmission power and pre-coding matrix indicator (PMI) of that PDSCH might be different. Plus some physical resource block (PRB) might be empty, which means no interference there. The interference cancellation performance will be much degraded without the resource allocation information for interference PDSCH.
However, how to indicate the resource allocation information for interference may require many bits to indicate resource allocation. Therefore it is not conventionally possible to put such information in the downlink control information (DCI) format. Also, the resource allocation of interference is dynamically changed every transmission time interval (TTI), so a radio resource control (RRC) configuration based solution is not fast enough.
Moreover, as mentioned above, conventional approaches consider interference cancellation with aligned PDSCH assignments only, which constrains evolved Node B (eNB) schedulers and may consume the gain from NAICS with the loss due to restricted scheduling.
In another conventional approach, radio network temporary identity (RNTI) space is divided up into groups, and a UE is required to search Das masked by RNTIs in each group, 8 or 16 RNTIs. As a result, the UE needs to perform many more additional blind decodings on the RNTIs in the group.